Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D235/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, condensed with other rings
  • C07D235/02—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, condensed with other rings condensed with carbocyclic rings or ring systems
  • C07D235/04—Benzimidazoles; Hydrogenated benzimidazoles
  • C07D235/24—Benzimidazoles; Hydrogenated benzimidazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
  • C07D235/30—Nitrogen atoms not forming part of a nitro radical
  • C07D235/32—Benzimidazole-2-carbamic acids, unsubstituted or substituted; Esters thereof; Thio-analogues thereof
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D235/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, condensed with other rings
  • C07D235/02—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, condensed with other rings condensed with carbocyclic rings or ring systems
  • C07D235/04—Benzimidazoles; Hydrogenated benzimidazoles
  • C07D235/24—Benzimidazoles; Hydrogenated benzimidazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
  • C07D235/28—Sulfur atoms
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P1/00—Drugs for disorders of the alimentary tract or the digestive system
  • A61P1/04—Drugs for disorders of the alimentary tract or the digestive system for ulcers, gastritis or reflux esophagitis, e.g. antacids, inhibitors of acid secretion, mucosal protectants
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
  • C07D401/02—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings
  • C07D401/12—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings linked by a chain containing hetero atoms as chain links

Definitions

• the present invention relates to a process for the preparation of compounds having a structure of 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazoles and that are used as antiulcer agents, to intermediate compounds used therein, and a method for their preparation.
• Proton pump inhibitors are a group of antiulcer agents having a structure of 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazoles, and among them are included the compounds with the International Nonproprietary Name (INN) omeprazole, pantoprazole, lansoprazole, rabeprazole, and esomeprazole (S-enantiomer of omeprazole).
• INN International Nonproprietary Name
• omeprazole pantoprazole
• lansoprazole lansoprazole
• rabeprazole rabeprazole
• esomeprazole S-enantiomer of omeprazole
• the enantiomers of these compounds have also been described, i.e, R-omeprazole, S-pantoprazole, R-pantoprazole, S-lansoprazole, R-lansoprazole, S-rabeprazole, and R-
• Proton pump inhibitors are disclosed, for example, in EP-A-0005129, EP-A-0166287, EP-A-0174726, EP-A-0268956, and WO-A-96/02535.
• the process normally used for the preparation of these compounds includes a common final step that consists in generating the sulphoxide group by oxidation of the corresponding sulphide:
• pantoprazole is obtained in a subsequent step by means of a nucleophilic substitution of the chlorine atom in the 4 position of the pyridine ring by a methoxy group.
• an object of the invention is a new process for the preparation of 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazoles and their pharmaceutically acceptable salts starting from easily obtainable intermediate compounds.
• Another object of this invention relates to new intermediate compounds for the preparation of 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazoles, as well as a process for the preparation of said intermediate compounds which are 2-benzimidazolylsulphinic acid derivatives.
• Another object of the invention is the use of these intermediate compounds in the preparation of 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazoles and their pharmaceutically acceptable salts.
• a further aspect of the invention relates to a process for preparing substantially optically pure 2-benzimidazolysulphinate intermediates, by fractionated crystallization.
• An object of the invention is a process for preparing the compounds of general formula (II) and their pharmaceutically acceptable salts
• the compounds have the general formula (II) wherein R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy partially or totally substituted with fluor atoms, more preferably R 2 is hydrogen, methoxy, or difluoromethoxy.
• the compound of general formula (II) is omeprazole, pantoprazole, lansoprazole or rabeprazole, their pharmaceutically acceptable salts.
• the starting material is a compound of general formula (I) as mentioned above.
• the compounds have the general formula (I) wherein R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy partially or totally substituted with fluor atoms, R is —OR 1 wherein R 1 is C 1 -C 4 alkyl, C 3 -C 12 cycloalkyl optionally substituted by one or more C 1 -C 4 alkyl groups, or C 7 -C 16 , alkylaryl and R 3 is hydrogen, alkali or alkaline earth metal cation, C 1 -C 4 alkyl, C 1 -C 4 alkyl partially or totally substituted with halogen atoms, alkenyl, sulfonylalkyl, sulfonylamino, carbonylalkyl, carbonyloxyalkyl or silylalkyl.
• R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy partially or totally substituted with fluor atoms
• R is —
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R is —OR 1 wherein R 1 is methyl, ethyl, n-propyl, i-propyl, ( ⁇ )-menthyl, (+)-menthyl, ( ⁇ )-fenchyl, (+)-fenchyl, ( ⁇ )-8-phenylmenthyl, (+)-8-phenylmenthyl, and R 3 is hydrogen, or alkali or alkaline earth metal cation.
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R is —OR 1 wherein R 1 is ethyl, ( ⁇ )-menthyl, or ( ⁇ )-fenchyl.
• the metalated derivatives of the compounds of formula (III) are metalated in the methyl group adjacent to the nitrogen atom of the pyridine ring. These derivatives may be obtained either from substituted 2-methylpyridines, which are described for example in EP-A-0005129, EP-A-0166287, EP-A-0174726, or EP-A-0268956, or from halomethyl derivatives of the substituted 2-methylpyridines by metalation reactions according to methods well known in the art.
• the metalated derivative of compound (III) is a compound of formula (VI)
• M′ is preferably a lithium cation.
• the compound of formula (III) is selected from the group consisting of compounds wherein R 4 is hydrogen or methyl, R 5 is methoxy, methyloxypropyloxy, or 2,2,2-trifluoroethoxy, and R 6 is methyl or methoxy.
• the compounds of formula (III) are selected from the group consisting of compounds wherein R 4 is hydrogen and R 5 and R 6 are methoxy; R 4 is hydrogen, R 5 is methyloxypropyloxy and R 6 is methyl; R 4 is methyl, R 5 is methoxy and R 6 is methyl; and R 4 is hydrogen, R 5 is 2,2,2-trifluoroethoxy, and R 6 is methyl.
• reaction between the compound of general formula (I) and the metalated derivative of the compound of formula (III) is carried out in the core of an inert solvent, for example, anhydrous tetrahydrofuran or anhydrous ethyl ether.
• anhydrous tetrahydrofuran is used.
• the metalation reaction for preparing the compound of formula (VI) may be carried out, for example, with n-butyl lithium at low temperature, in general, below ⁇ 80° C. in an inert solvent such as anhydrous tetrahydrofuran.
• the metalated derivative of the compound of formula (III) is not isolated, and the solution obtained is slowly added to a solution of the compound of general formula (I) in an inert solvent such as tetrahydrofuran, cooled to a low temperature normally below ⁇ 80° C. During the addition, the solution is usually maintained at low temperature, for example, below ⁇ 80° C.
• the resulting mixture is generally allowed to stand until reaching a temperature of approximately ⁇ 20° C. and then is allowed to reach room temperature after adding water.
• 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazoles can be prepared with a high degree of purity, since its use prevents the formation of impurities that can hardly be removed, such as sulphone and N-oxide sulphoxide derivatives, which are normally formed during the processes described for the preparation of said compounds. This fact contributes to avoiding complex purification methods and allows obtaining these compounds with a high yield.
• benzimidazole derivatives including omeprazole, pantoprazole, lansoprazole, and rabeprazole may be prepared by the process of the invention with a high yield.
• 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazoles compounds of general formula (II), have a sulphur atom bound to four different groups (where the pair of unshared electrons is considered to be another group, necessarily different from the others) and thus, optical activity may be present.
• proton pump inhibitors such as pantoprazole or omeprazole are, in fact, normally used in racemic form in pharmaceutical formulations, pure enantiomers may also be used, for example, esomeprazole which is the INN of S-enantiomer of omeprazole.
• each enantiomer of 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazoles may be prepared if the R group of the compound of general formula (I) is —OR 1 wherein R 1 is a chiral alcohol radical such as ( ⁇ )-menthol, (+)-menthol, ( ⁇ )-fenchol, (+)-fenchol, ( ⁇ )-8-fenylmentol, (+)-8-fenylmentol.
• R 1 is a chiral alcohol radical such as ( ⁇ )-menthol, (+)-menthol, ( ⁇ )-fenchol, (+)-fenchol, ( ⁇ )-8-fenylmentol, (+)-8-fenylmentol.
• the compound of general formula (I) is formed by a mixture of optical isomers.
• optical isomers which are diastereoisomers, is obtained, i.e. optical isomers that are not enantiomers.
• Enantiomers are those optical isomers, one of which is the mirror image of the other.
• the diastereoisomers normally show sufficiently different physical properties to be separated. For example, different solubilities in a same solvent.
• One of the methods that can be used for separating the optical isomers of the compound of general formula (I) consists of the use of a column for high-performance liquid chromatography designed for the separation of diastereoisomers, e.g., DISCOVERY ZR-CARBON column series supplied by Sigma-Aldrich.
• the preparation of the compound of general formula (II) by reaction between the compound of general formula (I) and the compound of formula (III) comprises a previous step, which comprises the separation of the optical isomers of the compound of general formula (I) wherein R 1 is a radical corresponding to a chiral alcohol.
• Chiral alcohols which may be used in the process of the invention, may be selected, for example, from the groups consisting of ( ⁇ )-menthol, (+)-menthol, ( ⁇ )-fenchol, (+)-fenchol, ( ⁇ )-8-phenylmenthol, and (+)-8-phenylmenthol.
• ( ⁇ )-menthol or ( ⁇ )-fenchol are used.
• one of the optical isomers of the compound of general formula (II) can be obtained in a stereospecific form. Consequently, S-omeprazole, R-omeprazole, S-pantoprazole, R-pantoprazole, S-lansoprazole, R-lansoprazole S-rabeprazole, and R-rabeprazole, and their pharmaceutically acceptable salts, may be obtained by means of the process of the invention.
• the compounds of formula (II) or its salt, obtained by the process of the invention may be directly used in solution as obtained, without isolation thereof, thus advantageously avoiding an isolation step with the consequent yield loss.
• the lithium salt of the compound of formula (II), preferably (S)-omeprazole lithium salt is not isolated and is directly used in solution as obtained to prepare the alkaline earth metal salt thereof, preferably the magnesium salt, by addition of an alkaline earth halogenide salt to said solution containing the lithium salt of the compound of formula (II).
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R is —OR 1 , wherein R 1 is methyl, ethyl, n-propyl, i-propyl, ( ⁇ )-menthyl, (+)-menthyl, ( ⁇ )-fenchil, (+)-fenchil, ( ⁇ )-8-phenylmenthyl, (+)-8-phenylmenthyl, and R 3 is hydrogen.
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R is —OR 1 wherein R 1 is ethyl, ( ⁇ )-menthyl, or ( ⁇ )-fenchyl.
• Group R 3 in the compound of general formula (I) may also be any protective group which is used for the protection of the amino group such as, for example, those protective groups reported by T. W. Greene et al., in “Protective Groups in Organic Synthesis”, 3rd Edition, John Wiley & Sons, New York, 1999 [ISBN: 0-471-16019-9].
• the starting material is a compound of general formula (IV) wherein R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms, R 3 is hydrogen or an alkali or alkaline earth metal cation, C 1 -C 4 alkyl, C 1 -C 4 alkyl partially or totally substituted with halogen atoms, alkenyl, sulfonylalkyl, sulfonylamino, carbonylalkyl, carbonyloxyalkyl or silylalkyl, and M is a alkali or alkaline earth metal cation.
• R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms
• R 3 is hydrogen or an alkali or alkaline earth metal cation
• R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms
• R 3 and M are an alkali or alkaline earth metal cation
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R 3 and M are a sodium or potassium cation.
• This customary technique is used, for example, for the preparation of carboxylic acid esters starting from the same acids, in which the —OH group is converted into a leaving group that can react with an alcohol.
• preparation of a mixed anhydride by reaction with carboxylic acid halides or with alkyl- or arylsulfonic acid halides, reaction with dicyclohexylcarbodiimide or N,N′-carbonyldiimidazole, reaction with ethyl azodicarboxylate (Mitsunobu esterification), reaction with dialkylhalophosphates, reaction with triflic anhydride, reaction with oxazolidinones of phosphinic acid halides, or the reaction with alkoxycarbonyl halides.
• the —OM group of the compound of general formula (IV) is converted into a leaving group by reaction of this compound with a compound selected from group consisting of oxazolidinones of phosphinic acid halides, alkoxycarbonyl halides, carboxylic acid halides, alkylcarbodiimides or N,N′-carbonyldiimidazole, more preferably the compound of the general formula (IV) is reacted with a C 2 -C 6 carboxylic acid chloride, more preferably with pivalic acid chloride.
• a compound selected from group consisting of oxazolidinones of phosphinic acid halides, alkoxycarbonyl halides, carboxylic acid halides, alkylcarbodiimides or N,N′-carbonyldiimidazole more preferably the compound of the general formula (IV) is reacted with a C 2 -C 6 carboxylic acid chloride, more preferably with pivalic acid chloride.
• Alkylcarbodiimides include, for instance, N′-dicyclohexylcarbodiimide.
• Oxazolidinones of phosphinic acid halides include, for instance, bis(2-oxo-3-oxazolidinyl)phosphinic acid chloride, which is commercially available and supplied, for example, by Aldrich.
• Alkoxycarbonyl halides include, for instance, ethyl chloroformiate.
• the activation reaction of the sulphinate group undergoes in the core of an inert solvent.
• a solvent selected from the group consisting of toluene, acetonitrile, dichloromethane, and chloroform is used, more preferably dichloromethane is used.
• the previous activation reaction may occur at a temperature ranging from ⁇ 20° C. to 20° C., preferably the reaction occurs at a temperature ranging from ⁇ 10° C. to 0° C.
• catalysts may be used such as for example 4-picoline or 4-dimethylaminopiridine.
• a molar excess of acid chloride is used versus starting material, i.e., the compound of general formula (IV). More preferably the molar excess ranges from 1.05 to 2.5, and even more preferably from 1.75 to 2.0.
• the subsequent reaction with an alcohol is usually carried out without isolating the activated intermediate, thus avoiding an isolation step with the consequent yield loss.
• reaction with the alcohol is advantageously carried out in the core of the same inert solvent used.
• the alcohol used to carry out this reaction is a C 1 -C 8 alkyl, C 2 -C 8 alkenyl, C 3 -C 20 cycloalkyl optionally substituted by one or more C 1 -C 4 alkyl groups or C 7 -C 20 alkylarylic alcohol.
• the alcohol is a C 1 -C 4 alkyl, C 3 -C 12 cycloalkyl optionally substituted by one or more C 1 -C 4 alkyl groups or C 7 -C 16 alkylaryl alcohol, more preferably the alcohol is methanol, ethanol, n-propanol, i-propanol, ( ⁇ )-menthol, (+)-menthol, ( ⁇ )-fenchol, (+)-fenchol, ( ⁇ )-8-phenylmenthol or (+)-8-phenyl menthol.
• the reaction with the alcohol may be carried out at a temperature ranging from ⁇ 10° C. to 5° C., preferably below 0° C.
• the compound of general formula (IV) are used, i.e., from 1.0 to 1.2 alcohol equivalents.
• the alcohol may be slowly added to a cold solution of the intermediate obtained.
• the same inert solvent e.g. methylene chloride
• the same inert solvent e.g. methylene chloride
• reaction mass After completion of addition, the reaction mass is allowed to stand until reaching room temperature generally over a period of 1 and 3 hours.
• the reaction product is treated by conventional methods for separation of the formed salts, for example, by adding water and subsequent separation of phases.
• pH of aqueous phase is adjusted to a range from 7 to 9.
• the compound of general formula (I) is obtained by evaporation of the organic phase and may be purified by methods known by a person skilled in the art, such as for example by recrystallization or column chromatography.
• a further aspect of the invention relates to a process for preparing substantially optically pure 2-benzimidazolylsulphinate intermediates.
• the present inventors have encountered difficulties when trying to separate by crystallization the diastereoisomers of the compounds of formula (I), when R 1 is a chiral alcohol radical. When the diastereoisomers where 100% in acid form no media resulted suitable for separating them by crystallization. However, the present inventors have identified that through partial or total formation of a salt of said diastereoisomers, they may be separated by fractionated crystallization.
• the present invention also provides a process for preparing a substantially optically pure compound of general formula (Ia)
• Rchi is ( ⁇ )-menthyl, (+)-menthyl, ( ⁇ )-fenchil, (+)-fenchil, ( ⁇ )-8-phenylmenthyl, (+)-8-phenylmenthyl, and R 2 is hydrogen, methoxy, or difluoromethoxy and R 3 is H, comprising the steps of: a) treating a racemic or a non-enantiomerically pure compound of formula (Ia) with a base in an organic solvent to form an salt of the compound of formula (Ia), and b) isolating the desired diastereomer of the compound of formula (Ia).
• R 2 is methoxy.
• Rchi is ( ⁇ )-menthyl.
• Suitable bases include sodium methyl acetoacetate, sodium methoxide, sodium hydride and potassium tert-butoxide.
• Preferably said base is sodium methyl acetoacetate.
• the fractionated crystallization is carried out in a polar aprotic organic solvent. More preferably tetrahydrofuran or acetonitrile. Yet more preferably, said solvent is acetonitrile.
• Step a) may be carried out at low temperatures, preferably at room temperature.
• the resulting product may be further purified to obtain the desired enantiomeric purity.
• Purification may be carried out by suspending or dissolving the solid in a suitable solvent.
• Preferably said purification is carried out in acetonitrile or methyl tert-butyl ether. More preferably in acetonitrile.
• the resulting product may be further converted to its 100% acid form by conventional procedures.
• the obtained product is a compound of the general formula (IV) wherein R 2 is hydrogen, C 1 -C 3 alkoxy, or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms, M is hydrogen or an alkali or alkaline earth metal cation, and R 3 is hydrogen or an alkali or alkaline earth metal cation, C 1 -C 4 alkyl, C 1 -C 4 alkyl partially or totally substituted with halogen atoms, alkenyl, sulfonylalkyl, sulfonylamino, carbonylalkyl, carbonyloxyalkyl or silylalkyl.
• R 2 is hydrogen, C 1 -C 3 alkoxy, or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms
• M is hydrogen or an alkali or alkaline earth metal cation
• R 3 is hydrogen or an alkali or alkaline earth metal cation
• R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms, and R 3 and M are an alkali or alkaline earth metal cation, and even more preferably R 2 is hydrogen, methoxy, or difluoromethoxy, and R 3 and M are a sodium or potassium cation.
• the oxidation may be carried out in the presence of peracids, such as for example m-chloroperbenzoic acid, or alkyl hydroperoxides such as t-butyl peroxide, or hydrogen peroxide and catalysis of molybdate salts.
• peracids such as for example m-chloroperbenzoic acid, or alkyl hydroperoxides such as t-butyl peroxide, or hydrogen peroxide and catalysis of molybdate salts.
• peracids such as for example m-chloroperbenzoic acid, or alkyl hydroperoxides such as t-butyl peroxide
• hydrogen peroxide and catalysis of molybdate salts Preferably hydrogen peroxide and catalysis of molybdate salts are used, and more preferably hydrogen peroxide and ammonium heptamolybdate are used.
• the oxidation reaction is carried out in an alkaline medium.
• the pH of the alkaline medium is basic, i.e., greater than 7.
• the reaction occurs preferentially on the core in an aqueous solution of an alkali or alkaline earth hydroxide, and more preferably sodium hydroxide.
• the starting material of general formula (V) is dissolved in the core of an aqueous alkali hydroxide solution, and then the mixture is cooled at a temperature ranging from ⁇ 20° C. to 20° C., preferably from ⁇ 10° C. to 10° C.
• the concentration of the aqueous alkali hydroxide solution preferably ranges from 0.1 N to 10 N, more preferably from 0.5 N to 2 N, and even more preferably 1 N approximately.
• ammonium heptamolybdate is added, the temperature is maintained below 0° C., and hydrogen peroxide is slowly added. Once the addition is completed, the resulting mixture is allowed to stand until reaching room temperature.
• the solvent may be removed under reduced pressure, and water traces may be eliminated from the product by methods well known in the art, for example, azeotropic distillation with toluene.
• the obtained product is sufficiently pure to be used directly as starting material for the preparation of the compound of general formula (I).
• the product may be later purified, for example, by esterification with an alcohol and subsequent akaline hydrolysis.
• the invention encompasses the intermediate compounds of general formula (I)
• the compounds have the general formula (I) wherein R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms, R is —OR 1 wherein R 1 is C 1 -C 4 alkyl, C 3 -C 12 cycloalkyl optionally substituted by one or more C 1 -C 4 alkyl groups or C 7 -C 16 alkylaryl and R 3 is hydrogen, alkali or alkaline earth metal cation, C 1 -C 4 alkyl, C 1 -C 4 alkyl partially or totally substituted with halogen atoms, alkenyl, sulfonylalkyl, sulfonylamino, carbonylalkyl, carbonyloxyalkyl or silylalkyl.
• R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms
• R is —OR 1 where
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R 1 is methyl, ethyl, n-propyl, i-propyl, ( ⁇ )-menthyl, (+)-menthyl, ( ⁇ )-fenchil, (+)-fenchil, ( ⁇ )-8-phenylmenthyl, (+)-8-phenylmenthyl
• R 3 is hydrogen.
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R 1 is ethyl, ( ⁇ )-menthyl, or ( ⁇ )-fenchil.
• the R 3 group in the compound of general formula (I) may also be any protective group that is used for the protection of the amino group, such as for example those mentioned in Greene's publication (see above).
• the compound of the invention is a compound of the general formula (I) wherein R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms, R is —OR 1 , wherein R 1 is an alkali or alkaline earth metal cation and R 3 is hydrogen or an alkali or alkaline earth metal cation. More preferably R 2 is hydrogen, methoxy, or difluoromethoxy, and R 1 and R 3 are an alkali metal cation, and even more preferably R 2 is hydrogen, methoxy, or difluoromethoxy, and R 1 and R 3 are a sodium cation or a potassium cation.
• R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms
• R is —OR 1 , wherein R 1 is an alkali or alkaline earth metal cation and R 3 is hydrogen or an alkali
• 2-benzimidazolylsulphinic acid derivatives are represented by the general formula (I)
• the compounds have the general formula (I) wherein R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms, R is —OR 1 wherein R 1 is C 1 -C 4 alkyl, C 3 -C 12 cycloalkyl optionally substituted by one or more C 1 -C 4 alkyl groups or C 7 -C 16 alkylaryl and R 3 is hydrogen, alkali or alkaline earth metal cation, C 1 -C 4 alkyl, C 1 -C 4 alkyl partially or totally substituted with halogen atoms, alkenyl, sulfonylalkyl, sulfonylamino, carbonylalkyl, carbonyloxyalkyl or silylalkyl.
• R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms
• R is —OR 1 where
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R 1 is methyl, ethyl, n-propyl, i-propyl, ( ⁇ )-menthyl, (+)-menthyl, ( ⁇ )-fenchil, (+)-fenchil, ( ⁇ )-8-phenylmenthyl, (+)-8-phenylmenthyl
• R 3 is hydrogen or alkali or alkaline earth metal cation.
• R 2 is hydrogen, methoxy, or difluoromethoxy
• R 1 is ethyl, ( ⁇ )-menthyl, or ( ⁇ )-fenchil.
• the compound of the invention is a compound of general formula (I) wherein R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms, R is —OR 1 , wherein R 1 is a alkali or alkaline earth metal cation, and R 3 is hydrogen or an alkali or alkaline earth metal cation. More preferably R 2 is hydrogen, methoxy, or difluoromethoxy, and R 1 and R 3 are an alkali metal cation, and even more preferably R 2 is hydrogen, methoxy, or difluoromethoxy, and R 1 and R 3 are a sodium cation or a potassium cation.
• R 2 is hydrogen, C 1 -C 3 alkoxy or C 1 -C 3 alkoxy totally or partially substituted with fluor atoms
• R is —OR 1 , wherein R 1 is a alkali or alkaline earth metal cation, and R 3 is hydrogen or an
• 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazole derivatives that are prepared from the compounds of general formula (I) are omeprazole, pantoprazole, lansoprazole, rabeprazole, esomeprazole (S-omeprazole), R-omeprazole, S-pantoprazole, R-pantoprazole, S-lansoprazole, R-lansoprazole, S-rabeprazole, and R-rabeprazole.
• the 2-(2-pyridylmethyl)sulphinyl-1H-benzimidazole derivatives and their pharmaceutically salts obtained by the process of the invention may be used for the formulation of antiulcer drugs such as those described, for example, in EP-A-0005129, EP-A-0166287, EP-A-0174726, and EP-A-0268956.
• 2-mercapto-5-methoxybenzimidazole may be prepared in accordance with the method described in EP-A-0005129 or may be obtained from commercial sources (Aldrich).
• the pure product was obtained as a monohydrate by esterification with ( ⁇ )-menthyl and subsequent basic hydrolysis.
• the novel product was characterized by means of melting point, infrared spectrum (IR), 1 H and 13 C nuclear magnetic resonance (NMR), and mass spectrometry, showing the following results:
• 2-mercapto-5-difluoromethoxybenzimidazole may be prepared in accordance with the process in EP-A-166287.
• 2-mercaptobenzimidazole may be obtained from commercial sources (Fluka).
• the obtained crude product was purified by column chromatography (silica gel), using heptane/ethyl acetate (4:1) as eluent.
• the novel compound was characterized by means of melting point, infrared spectrum (IR), 1 H and 13 C nuclear magnetic resonance (NMR), elemental analysis and mass spectrometry, showing the following results:
• a white solid was obtained with a total yield of 51% corresponding to the two steps performed starting from 2-mercapto-5-methoxybenzimidazole.
• the novel compound was characterized by means of melting point, infrared spectrum (IR), 1 H and 13 C nuclear magnetic resonance (NMR), elemental analysis and mass spectrometry, showing the following results:
• the novel compound was characterized by means of melting point, infrared spectrum (IR), 1 H and 13 C nuclear magnetic resonance (NMR) and mass spectrometry, showing the following results:
• the novel compound was characterized by means of melting point, infrared spectrum (IR), 1 H and 13 C nuclear magnetic resonance (NMR), elemental analysis and mass spectrometry, showing the following results:
• the novel compound was characterized by means of melting point, infrared spectrum (IR), 1 H and 13 C nuclear magnetic resonance (NMR) and mass spectrometry, showing the following results:
• 4-methoxy-2,3,5-trimethylpiridine may be prepared in accordance with the process described in EP-A-0005129.
• the resulting mixture was allowed to stand up to ⁇ 20° C., then 20 ml of water were slowly added and it was allowed to reach room temperature.
• reaction mixture was analyzed by HPLC, and conversion and yield were found to be 99% and 86% respectively.
• 2,3-dimethyl-4-(3-methoxy-propoxy)pyridine may be prepared in accordance with the process described in EP-A-0268956.
• the resulting mixture was allowed to stand up to ⁇ 20° C., then 100 ml of water were slowly added and it was allowed to reach room temperature.
• reaction mixture was analyzed by HPLC, and conversion and yield were found to be 95% and 90% respectively.
• Solvent consisted of a mixture of 10% water, 80% acetonitrile, and 10% tetrahydrofuran (10:80:10, v/v/v).
• the resulting mixture was allowed to stand up to ⁇ 20° C., then 5 ml of water were slowly added and it was allowed to reach room temperature.
• reaction mixture was analyzed by HPLC and 92% conversion occurred.
• the resulting mixture was allowed to warm to about ⁇ 60° C., 90 mL of water were added slowly, and the mixture was allowed to warm to room temperature. Over said solution, 50 mL of dichloromethane were added and the organic phase was separated. The aqueous phase (pH aprox 12-13) was washed with dichloromethane (1 ⁇ 50 mL).
• the pH of the aqueous phase was adjusted to 10.5-11.5 with hydrogen chloride. Over the resulting solution at a temperature between 5-20° C., a solution of hexahydrated magnesium chloride (0.915 g, 4.5 mmol) in 5 mL of water was added. A whitish precipitate was formed immediately and was filtered and washed with water (2 ⁇ 15 mL) at room temperature.

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• 2007
  • 2007-05-18 EP EP07380144A patent/EP1992619A1/en not_active Withdrawn
• 2008
  • 2008-05-15 WO PCT/EP2008/055997 patent/WO2008142006A1/en active Application Filing
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